Motor compressor

ABSTRACT

An object is to maintain housings at equal potentials. Facing insertion holes are formed on mating surfaces of a front housing and a center housing. One end and the other end of a spring pin are inserted into the insertion holes, respectively, and an outer peripheral surface is pressed against inner peripheral surfaces of the insertion holes by an elastic force.

TECHNICAL FIELD

The present invention relates to a motor compressor.

BACKGROUND ART

In a motor compressor, an inverter accommodation portion and a cover areinsulated by a gasket. PTL 1 proposes that a projection portion formedin the inverter accommodation portion is brought into contact with thecover to maintain both at equal potentials.

CITATION LIST Patent Literature

PTL 1: JP 2015-17577 A

SUMMARY OF INVENTION Technical Problem

The motor compressor is formed by assembling a plurality of housings,and each housing is also insulated by a gasket. Therefore, it isnecessary to take measures to maintain each housing at equal potentials.

An object of the present invention is to maintain the housings at equalpotentials.

Solution to Problem

A motor compressor according to an aspect of the present inventionincludes: a first housing and a second housing each made of metal, andconfigured to be insulated from each other by interposing a gasketbetween mating surfaces, in which facing insertion holes are formed inportions of the mating surfaces where the gasket is not provided; and aninsertion member made of metal, and having one end and the other endwhich are inserted into the insertion holes, respectively, and an outerperipheral surface which is pressed against inner peripheral surfaces ofthe insertion holes by an elastic force.

Advantageous Effects of Invention

According to the present invention, since the outer peripheral surfaceof the insertion member is pressed against the inner peripheral surfaceof the insertion hole by the elastic force, sufficient surface contactcan be maintained and the housings can be maintained at equalpotentials.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a cross-sectional view of a compressor along an axialdirection;

FIG. 2 is a diagram illustrating a spring pin; and

FIGS. 3A and 3B are diagrams each illustrating a comparative example.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of the present invention will be described withreference to the drawings. Each drawing is a schematic one and maydiffer from the actual one. In addition, the following embodimentsexemplify a device and a method for embodying a technical idea of thepresent invention, and do not specify a configuration to the following.That is, the technical idea of the present invention can be modified invarious ways within the technical scope described in Claims.

One Embodiment

<<Configuration>>

FIG. 1 is a cross-sectional view of a compressor along an axialdirection.

A compressor 11 is, for example, a motor compressor used in arefrigerant circuit of a car air conditioner, sucks a refrigerant,compresses the refrigerant, and then discharges the refrigerant.

In the following description, for convenience, one side in the axialdirection of the compressor 11 is referred to as a front side, and theother side in the axial direction is referred to as a rear side.

The compressor 11 is integrated with a front housing 12, a centerhousing 13, and a rear housing 14 disposed in order from the front sidealong the axial direction to maintain airtightness. The front housing 12is formed with a suction port (not illustrated) for sucking therefrigerant, and the rear housing 14 is formed with a discharge port(not illustrated) for discharging the compressed refrigerant.

The front housing 12 includes a suction chamber 21 communicating withthe suction port (not illustrated), and an electric motor 22 is housedin the suction chamber 21. A rotating shaft 23 of the electric motor 22is rotatably supported on the front side by the front housing 12 and isrotatably supported on the rear side by the center housing 13.

A fixed scroll 24 and a movable scroll 25 are housed in the centerhousing 13.

The fixed scroll 24 is fixed to close the rear side of the front housing12, and includes a fixed endplate 26 formed in a disk shape and a fixedspiral 27 formed on a front surface of the fixed end plate 26.

The movable scroll 25 is disposed on the front side of the fixed endplate 26, and includes a movable end plate 28 formed in a disk shape anda movable spiral 29 formed on a rear surface of the movable endplate 28and meshing with the fixed spiral 27.

The front surface of the fixed endplate 26 and the rear surface of themovable end plate 28 face each other, and the fixed spiral 27 and themovable spiral 29 mesh with each other. A tip end of the fixed spiral 27slidably contacts the rear surface of the movable end plate 28 via a tipseal (not illustrated), and a tip end of the movable spiral 29 slidablycontacts the front surface of the fixed end plate 26. A compressionchamber 31 for compressing the refrigerant is formed by a sectionsurrounded by the front surface of the fixed end plate 26, the fixedspiral 27, the rear surface of the movable end plate 28, and the movablespiral 29. When viewed from a front-rear direction, the compressionchamber 31 is a crescent-shaped closed space.

A back pressure chamber 32 is formed on a front side of the movablescroll 25. By supplying oil of intermediate pressure to the backpressure chamber 32, the movable scroll 25 is pressed against the fixedscroll 24 to improve the airtightness of the compression chamber 31.

A boss 33 is formed on a front surface of the movable end plate 28, aneccentric crank end portion 34 is formed on the rear end of the rotatingshaft 23, and the crank end portion 34 is rotatably fitted into the boss33. The rotational movement of the rotating shaft 23 is transmitted tothe movable scroll 25 as a turning movement by the crank end portion 34.The movable scroll 25 is prevented from rotating through, for example, apin and a hole, and is allowed to revolve with respect to the fixedscroll 24.

A discharge hole 35 penetrating in the front-rear direction is formed inthe center of the fixed end plate 26, and the discharge hole 35communicates with a discharge chamber 36 formed on the rear side of thefixed endplate 26. A discharge valve 37 that can open and close the rearend side of the discharge hole 35 is provided on a rear surface of thefixed end plate 26.

When the movable scroll 25 revolves with respect to the fixed scroll 24,the compression chamber 31 is displaced toward the scroll center whenviewed from the front-rear direction, and the volume is reduced. Whenthe compression chamber 31 is outside the scroll, the compressionchamber 31 communicates with a suction port (not illustrated) to suckthe refrigerant. When the compression chamber 31 is in the center of thescroll, the compression chamber 31 communicates with the discharge hole35 to discharge the compressed refrigerant. When the discharge valve 37receives the discharge pressure, the discharge valve 37 discharges therefrigerant into the discharge chamber 36. The discharged refrigerant isdischarged to the outside from a discharge port (not illustrated).

Next, an equipotential structure of each housing will be described.

The front housing 12 (first housing), the center housing 13 (secondhousing), and the rear housing 14 (third housing) are all made of metal.The front housing 12 and the center housing 13 are insulated from eachother by interposing a gasket 41 whose surface layer is rubber betweenthe mating surfaces. The center housing 13 and the rear housing areinsulated from each other by interposing a gasket 42 whose surface layeris rubber between the mating surfaces. The front housing 12 and the rearhousing 14 are fastened with bolt 43 with the center housing 13interposed therebetween. An inserting hole 44 having a diameter largerthan that of the bolt 43 is formed in the center housing 13, the bolt 43is inserted into the inserting hole 44, and each housing is assembled.

Therefore, the front housing 12 and the rear housing 14 are maintainedat equal potentials by the bolt 43. On the other hand, in the centerhousing 13, since the bolt 43 is loosely inserted into the insertinghole 44, a contact state is not stable and the equipotential is notguaranteed. The front housing 12 and the center housing 13 are connectedby a spring pin 45 (insertion member), and the equipotential ismaintained.

FIG. 2 is a diagram illustrating a spring pin.

Facing insertion holes 46 are formed on the mating surfaces of the fronthousing 12 and the center housing 13, respectively. The two insertionholes 46 have the same diameter and are formed coaxially. The diameterof the insertion hole 46 is slightly smaller than the outer diameter ofthe spring pin 45. The gasket 41 is formed with an opening portion 47(portion without a gasket) penetrating from the front housing 12 side tothe center housing 13 side at a position corresponding to the insertionholes 46.

The spring pin 45 is used for positioning in the circumferentialdirection when fixing the front housing 12 and the center housing 13,and one end and the other end are inserted into the respective insertionholes 46. The spring pin 45 is formed by winding a thin plate in acylindrical shape, and includes a cut line 48 along the axial direction.When no load is applied from the outside, since the cut line 48 isseparated in the circumferential direction, the spring pin 45 has asubstantially C shape when viewed from the axial direction. The outerdiameter of the spring pin 45 is wide open toward the rear side in theaxial direction, and is slightly larger than that of the insertion hole46. When inserting the spring pin 45 into the insertion hole 46, a loadin the diameter reduction direction is applied to the spring pin 45 andthe spring pin 45 is press-fitted so that the cut line 48 is eliminated.The spring pin 45 inserted into the insertion hole 46 is fixed to theinsertion hole 46 by the action of a force that tries to spread. Theouter peripheral surface of the spring pin 45 is pressed against theinner peripheral surfaces of the insertion holes 46 by an elastic force,and a stable surface contact state is established.

<<Action>>

Next, the main action and effect of one embodiment will be described.

The front housing 12 and the center housing 13 are insulated by thegasket 41, and the center housing 13 and the rear housing 14 areinsulated by the gasket 42. However, the compressor 11 is required tomaintain each housing at equal potentials. The front housing 12 and therear housing 14 are maintained at equal potentials by the bolt 43. Onthe other hand, in the center housing 13, since the bolt 43 is looselyinserted into the inserting hole 44, a contact state is not stable andthe equipotential is not guaranteed.

Therefore, the front housing 12 and the center housing 13 are connectedby the spring pin 45. That is, the facing insertion holes 46 are formedon the mating surfaces of the front housing 12 and the center housing13, respectively, and one end and the other end of the spring pin 45 areinserted into the respective insertion holes 46. The spring pin 45inserted into the insertion hole 46 is kept in sufficient surfacecontact because the outer peripheral surface of the spring pin 45 ispressed against the inner peripheral surface of the insertion hole 46 bythe action of a force that tries to spread. Therefore, the front housing12 and the center housing 13 can be maintained at equal potentials.

The front housing 12 and the center housing 13 are originally formedwith the insertion holes 46 for inserting solid pins (also referred toas knock pins) for positioning in the circumferential direction.Therefore, the solid pin to be inserted into the insertion hole 46 mayonly be changed to the spring pin 45.

Here, a comparative example will be described.

FIGS. 3A and 3B are diagrams each illustrating a comparative example.

FIG. 3A illustrates a case where a solid pin 51 is used. Since the solidpin 51 is a simple columnar member and does not press the outerperipheral surface against the inner peripheral surfaces of theinsertion holes 46 by an elastic force, the action and effect as in thepresent embodiment cannot be obtained. In a case of light press-fitting,an equipotential value is unstable due to vibration fretting becausethere is no pressing force. In addition, in a case of strongpress-fitting, there is a concern that galling of the pin and housingmay occur in production.

FIG. 3B illustrates a case where the solid pin 51 is used and thecenters of the insertion holes 46 are intentionally shifted from eachother. As a result, both ends of the solid pin 51 can be brought intoline contact with the inner peripheral surfaces of the insertion holes46. However, since the outer peripheral surface of the solid pin 51 isnot pressed against the inner peripheral surfaces of the insertion holes46 by an elastic force, the action and effect as in the presentembodiment cannot be obtained. Specifically, when a continuity test wasperformed, it was found that the resistance value may not be apredetermined threshold value (for example, 10 mΩ) or less, and theresistance value varied widely.

<<Modification>>

In the present embodiment, the spring pin 45 is used, and the presentinvention is not limited thereto. For example, a leaf spring portion maybe formed at the tip end of the pin so that the leaf spring portionelastically deforms and comes into surface contact with the innerperipheral surface of the insertion hole 46. As described above, anyshape can be used as long as the outer peripheral surface of theinsertion member is pressed against the inner peripheral surface of theinsertion hole by an elastic force.

Hereinbefore, although described with reference to a limited number ofembodiments, the scope of rights is not limited thereto, andmodifications of the embodiments based on the above disclosure areobvious to those skilled in the art.

REFERENCE SIGNS LIST

-   -   11 compressor    -   12 front housing    -   13 center housing    -   14 rear housing    -   21 suction chamber    -   22 electric motor    -   23 rotating shaft    -   24 fixed scroll    -   25 movable scroll    -   26 fixed end plate    -   27 fixed spiral    -   28 movable end plate    -   29 movable spiral    -   31 compression chamber    -   32 back pressure chamber    -   33 boss    -   34 crank end portion    -   35 discharge hole    -   36 discharge chamber    -   37 discharge valve    -   41 gasket    -   42 gasket    -   43 bolt    -   44 inserting hole    -   45 spring pin    -   46 insertion hole    -   47 opening portion    -   48 cut line    -   51 solid pin

1. A motor compressor comprising: a first housing and a second housingeach made of metal, and configured to be insulated from each other byinterposing a gasket between mating surfaces, in which facing insertionholes are formed in portions of the mating surfaces where the gasket isnot provided; and an insertion member made of metal, and having one endand the other end which are inserted into the insertion holes,respectively, and an outer peripheral surface which is pressed againstinner peripheral surfaces of the insertion holes by an elastic force. 2.The motor compressor according to claim 1, wherein the insertion memberis a spring pin.
 3. The motor compressor according to claim 1, whereinthe insertion member is used for positioning in a circumferentialdirection when fixing the first housing and the second housing.
 4. Themotor compressor according to claim 1, further comprising: a thirdhousing made of metal, and configured to be fastened to the firsthousing by a bolt with the second housing interposed between the firsthousing and the third housing, and be insulated from the second housingby placing a gasket on a mating surface with the second housing, whereinthe second housing includes an inserting hole having a diameter largerthan that of the bolt.
 5. The motor compressor according to claim 2,wherein the insertion member is used for positioning in acircumferential direction when fixing the first housing and the secondhousing.
 6. The motor compressor according to any one of claim 2,further comprising: a third housing made of metal, and configured to befastened to the first housing by a bolt with the second housinginterposed between the first housing and the third housing, and beinsulated from the second housing by placing a gasket on a matingsurface with the second housing, wherein the second housing includes aninserting hole having a diameter larger than that of the bolt.
 7. Themotor compressor according to claim 3, further comprising: a thirdhousing made of metal, and configured to be fastened to the firsthousing by a bolt with the second housing interposed between the firsthousing and the third housing, and be insulated from the second housingby placing a gasket on a mating surface with the second housing, whereinthe second housing includes an inserting hole having a diameter largerthan that of the bolt.
 8. The motor compressor according to claim 5,further comprising: a third housing made of metal, and configured to befastened to the first housing by a bolt with the second housinginterposed between the first housing and the third housing, and beinsulated from the second housing by placing a gasket on a matingsurface with the second housing, wherein the second housing includes aninserting hole having a diameter larger than that of the bolt.